The use of 4-Hexylresorcinol as antibiotic adjuvant.

Ever decreasing efficiency of antibiotic treatment due to growing antibiotic resistance of pathogenic bacteria is a critical issue in clinical practice. The two generally accepted major approaches to this problem are the search for new antibiotics and the development of antibiotic adjuvants to enhance the antimicrobial activity of known compounds. It was therefore the aim of the present study to test whether alkylresorcinols, a class of phenolic lipids, can be used as adjuvants to potentiate the effect of various classes of antibiotics. Alkylresorcinols were combined with 12 clinically used antibiotics. Growth-inhibiting activity against a broad range of pro- and eukaryotic microorganisms was determined. Test organisms did comprise 10 bacterial and 2 fungal collection strains, including E. coli and S. aureus, and clinical isolates of K. pneumoniae. The highest adjuvant activity was observed in the case of 4-hexylresorcinol (4-HR), a natural compound found in plants with antimicrobial activity. 50% of the minimal inhibitory concentration (MIC) of 4-HR caused an up to 50-fold decrease in the MIC of antibiotics of various classes. Application of 4-HR as an adjuvant revealed its efficiency against germination of bacterial dormant forms (spores) and prevented formation of antibiotic-tolerant persister cells. Using an in vivo mouse model of K. pneumoniae-induced sepsis, we could demonstrate that the combination of 4-HR and polymyxin was highly effective. 75% of animals were free of infection after treatment as compared to none of the animals receiving the antibiotic alone. We conclude that alkylresorcinols such as 4-HR can be used as an adjuvant to increase the efficiency of several known antibiotics. We suggest that by this approach the risk for development of genetically determined antibiotic resistance can be minimized due to the multimodal mode of action of 4-HR.

[Oral cavity microbiocenosis assessment on the basis of bacterial endotoxin and plasmalogens in a saliva by method GAS-liquid chromatography-mass spectrometry.]

The concentration of plasmalogen bacterial and endotoxin levels in the saliva of patients with different severity of periodontal disease, injury prosthetic bed and with various degrees of the oral cavity microbiocenosis violations was studied. Determination of the presence of the pathological process was carried out clinically, according to the condition of periodontal tissues. The degree of microbiological disorders was assessed by the quantitative ratio of the types of microorganisms isolated from the smear taken from the gingival groove. It was found that the concentration of plasmalogen for normal microbiocenosis is not less than 0.7 µg/g. For the intermediate type of microbiocenosis, the concentration of 1.82 µg/g was determined; for dysbiosis - 5.64 µg/g, and for the expressed violation of the microbial composition accompanied by inflammatory processes - 6.54 µg/g. An increase in the concentration of bacterial endotoxin (be) more than 6.25 nanomole/g indicates the pronounced inflammatory process, regardless of the determined intensity of contamination of opportunistic gram-negative microflora.

[Rapid analysis of suppositories by quantitative 1H NMR spectroscopy].

Rapid analysis of suppositories with ibuprofen and arbidol by quantitative 1H NMR spectroscopy was performed. Optimal conditions for the analysis were developed. The results are useful for design of rapid methods for quality control of suppositories with different components

[Investigation of structural characteristics of initial substances of ibuprofen and micronization impact].

Structural characteristics of ibuprofen substances manufactured by different firms and the impact of micronization on them were compared. The study showed that the use of X-ray diffraction methods was necessary for certification of medicinals (crystalline) since only such methods provided information on the substance crystal structure, the molecular state and polymorphous forms.

[Scientific approaches to development of medicinal formulation based on biotechnological substance].

The study demonstrated possible design of a medicinal formulation in the form of suppositories comprising human recombinant interferon-alpha2 and dry aloe extract. The approaches to the development of the suppositories were technology-derived. No interaction between the active and auxiliary components was proved by solid state 1H-NMR spectroscopy. The specific activity of the drug was investigated.

Computational redesign of a protein-protein interface for high affinity and binding specificity using modular architecture and naturally occurring template fragments.

A new method is presented for the redesign of protein-protein interfaces, resulting in specificity of the designed pair while maintaining high affinity. The design is based on modular interface architecture and was carried out on the interaction between TEM1 beta-lactamase and its inhibitor protein, beta-lactamase inhibitor protein. The interface between these two proteins is composed of several mostly independent modules. We previously showed that it is possible to delete a complete module without affecting the overall structure of the interface. Here, we replace a complete module with structure fragments taken from nonrelated proteins. Nature-optimized fragments were chosen from 10(7) starting templates found in the Protein Data Bank. A procedure was then developed to identify sets of interacting template residues with a backbone arrangement mimicking the original module. This generated a final list of 361 putative replacement modules that were ranked using a novel scoring function based on grouped atom-atom contact surface areas. The top-ranked designed complex exhibited an affinity of at least the wild-type level and a mode of binding that was remarkably specific despite the absence of negative design in the procedure. In retrospect, the combined application of three factors led to the success of the design approach: utilizing the modular construction of the interface, capitalizing on native rather than artificial templates, and ranking with an accurate atom-atom contact surface scoring function.

Binding hot spots in the TEM1-BLIP interface in light of its modular architecture.

Proteins bind one another in aqua's solution to form tight and specific complexes. Previously we have shown that this is achieved through the modular architecture of the interaction network formed by the interface residues, where tight cooperative interactions are found within modules but not between them. Here we extend this study to cover the entire interface of TEM1 beta-lactamase and its protein inhibitor BLIP using an improved method for deriving interaction maps based on REDUCE to add hydrogen atoms and then by evaluating the interactions using modifications of the programs PROBE, NCI and PARE. An extensive mutagenesis study of the interface residues indeed showed that each module is energetically independent on other modules, and that cooperativity is found only within a module. By solving the X-ray structure of two interface mutations affecting two different modules, we demonstrated that protein-protein binding occur via the structural reorganization of the binding modules, either by a "lock and key" or an induced fit mechanism. To explain the cooperativity within a module, we performed multiple-mutant cycle analysis of cluster 2 resulting in a high-resolution energy map of this module. Mutant studies are usually done in reference to alanine, which can be regarded as a deletion of a side-chain. However, from a biological perspective, there is a major interest to understand non-Ala substitutions, as they are most common. Using X-ray crystallography and multiple-mutant cycle analysis we demonstrated the added complexity in understanding non-Ala mutations. Here, a double mutation replacing the wild-type Glu,Tyr to Tyr,Asn on TEM1 (res id 104,105) caused a major backbone structural rearrangement of BLIP, changing the composition of two modules but not of other modules within the interface. This shows the robustness of the modular approach, yet demonstrates the complexity of in silico protein design.

[Preclinical investigation and standardization of metronidazole soft dosage forms].

Comparative acute and subacute toxicity of Dentamet gel and Metrovagin suppositories manufactured by ZAO Altaivitaminy was studied with using analogous drugs, i. e. Metrogil Denta, a gel for the gingivae, manufactured by Unique Pharmaceutical Laboratories (India), and Flagil manufactured by Haupt Farma Livron (France) as the reference drugs. It was shown that the drugs induced no changes in the exterior, hair state, body weight and mobility of the experimental animals vs. the control. The pharmacokinetic study of Metrovagin vaginal suppositories vs. the registered analogous drug Flagil showed that Metrovagin was bioequivalent to Flagil. The relative bioavailability of the new drug vs. the control was 103.13%.

[Determination of biological activity of hydrogel preparations based on ketoconazole and clotrimazole]. / Opredelenie biologicheskoi aktivnosti gidrogelevykh preparatov na osnove ketokonazola i klotrimazola.

Biological activity of original hydrogel preparations based on ketoconazole and clotrimazole was estimated biologically with the 3-dose variant of the agar-diffusion method. The optimal concentrations of the active substances in the hydrogels were the following: 2% of ketoconazole and 1% for clotrimazole.